Core Web Vitals

Core Web Vitals Definition:

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Core Web Vitals are a set of specific factors that Google considers important in a webpage's overall user experience. As of 2021, these vitals are composed of three specific page speed and user interaction measurements: Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). These metrics help site owners measure user experience in terms of loading performance, interactivity, and visual stability.

Understanding and Optimizing Core Web Vitals for Better User Experience

Core Web Vitals, are a set of factors deemed crucial to a webpage’s overall user experience. They consist of three specific measurements: Largest Contentful Paint (LCP), First Input Delay (FID), and Cumulative Layout Shift (CLS). These metrics help gauge the user experience in terms of loading performance, interactivity, and visual stability.

1. Largest Contentful Paint (LCP):

This metric measures the load speed and marks the point in the page load timeline when the main Content is likely to have loaded. A good LCP score helps reassure users that the page is useful.

2. First Input Delay (FID):

FID measures the time from when a user first interacts with a page (when they click a link, tap a button, etc.) to the time when the browser begins to process that interaction. A good FID score gives users the feeling that the page is reliable.

3. Cumulative Layout Shift (CLS):

CLS measures the visual stability of a page. It quantifies the amount a page’s content unexpectedly shifts around. A low CLS score ensures the page is enjoyable to users.

Understanding and optimizing these Core Web Vitals can significantly enhance user experience, which in turn, can help improve your site’s SEO performance. Google has incorporated Core Web Vitals into their ranking algorithm, indicating the increasing importance of page experience in search results.

Optimizing Core Web Vitals requires a systematic approach:

1. Measure Performance: Use tools like Google’s PageSpeed Insights or Lighthouse to measure your page performance.

2. Optimize Content Efficiency: Ensure your site’s content is efficiently coded and sized appropriately to load quickly.

3. Improve Interactivity: Optimize your JavaScript parsing and execution process to ensure quick responsiveness to user interactions.

4. Ensure Visual Stability: Avoid inserting content above existing content, unless in response to a user interaction, to prevent unexpected layout shifts.

In conclusion, Core Web Vitals are an essential part of a webpage’s overall user experience. By understanding and optimizing these vitals, website owners can not only enhance the user experience but also potentially boost their site’s SEO performance.

Adapting to Google’s Core Web Vitals Update

  1. Understand Core Web Vitals Metrics:
    • Largest Contentful Paint (LCP): Page loading speed.
    • First Input Delay (FID): Interactivity and responsiveness.
    • Cumulative Layout Shift (CLS): Visual stability.
  2. Improve Page Loading Speed (LCP):
    • Use modern image formats like WebP, which offer better compression than PNG or JPEG.
    •  Use this tool to convert images to WebP format.
    • Use lazy loading. This will load images only when they enter or are about to enter the viewport using the loading=”lazy” attribute for img tags.
    • Use srcset to deliver multiple image sizes, allowing browsers to choose the best fit.
    • Minimize CSS and JavaScript. Reduce the size of CSS and JS files by removing unnecessary characters, like whitespace and comments.
    • Implement server caching.
    • Utilize Content Delivery Networks or (CDNs) to serve content from the nearest location to your users.
    • Use the latest versions of PHP
    • Use Gzip or Brotli to compress your assets.
    • Eliminate Render-blocking Resources by deferring non-critical CSS and JavaScript when possible. <script src=”myscript.js” defer>
    • Use the rel=”preload” attribute to load crucial resources earlier.
    • Given the rise of mobile browsing, ensure that your site is responsive and performs well on mobile networks and devices.
    • Third-party scripts can significantly delay LCP times. Audit these scripts and only use what’s necessary.
  3. Enhance Interactivity and Responsiveness (FID):
    • Minimize or defer JavaScript.
    • Use a web worker for complex calculations.
    • Optimize server response times.
    • Implement proper error handling.
  4. Stabilize Layout and Reduce Shifts (CLS):
    • Specify image dimensions.
    • Allocate space for ads and embeds.
    • Avoid adding content above existing content unless responding to user interaction.
    • Utilize CSS aspect ratio boxes.
  5. Utilize Google’s Tools:
    • Check Core Web Vitals report in Google Search Console.
    • Test pages with Google’s PageSpeed Insights and Lighthouse.
    • Use Chrome DevTools for in-depth analysis.
  6. Optimize Mobile Experience:
    • Test and improve mobile responsiveness.
    • Focus on touch-friendly design and navigation.
  7. Implement Proper Accessibility:
    • Follow accessibility guidelines to ensure a broad range of users can access your site.
    • Test accessibility using appropriate tools.
  8. Monitor Server Performance:
    • Optimize server response times.
    • Regularly monitor server load.
    • Consider upgrading hosting if needed.
  9. Keep Third-Party Scripts in Check:
    • Review and minimize third-party scripts.
    • Load non-essential third-party scripts after key content.
  10. Regularly Review and Update Content:
    • Keep content fresh and relevant.
    • Remove or update outdated elements that may affect performance.
  11. Implement Best Practices for CSS and JavaScript:
    • Minimize or inline critical CSS.
    • Defer non-critical CSS.
    • Asynchronously load non-critical JavaScript.
  12. Work with a Cross-Functional Team:
    • Collaborate with developers, designers, and SEO specialists.
    • Encourage regular communication and updates.
  13. Monitor Competitor Performance:
    • Keep an eye on how competitors are adapting to Core Web Vitals.
    • Adjust strategies as needed to stay competitive.
  14. Stay Informed about Updates:
    • Follow Google’s updates on Core Web Vitals.
    • Participate in SEO communities and forums.
  15. Create a Continuous Improvement Plan:
    • Establish regular performance checks.
    • Encourage ongoing optimization efforts.

Core Web Vitals QUOTE:

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"Core Web Vitals are the subset of Web Vitals that apply to all web pages, should be measured by all site owners, and will be surfaced across all Google tools." - Google
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Article By: Nathan Ergang


Nathan Ergang, the web developer behind, he has over a decade of WordPress and online marketing expertise. His venture into the expansive universe of web development started in 2012, though his passion for personal projects took root much earlier. A practitioner of multiple web languages such as PHP, JavaScript, jQuery, CSS, and Python, Nathan has also deep-dived into SEO and possesses a keen eye for graphic design. Green Marketing, a venture close to Nathan's heart, stands testament to his entrepreneurial drive and commitment. Outside the digital domain, Nathan savors life's simpler pleasures. He cherishes traveling, often venturing off the beaten path, and has a knack for capturing the essence of a moment through photography and videography.

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